1. Field of the Disclosure
The present disclosure relates generally to media sensors used in imaging systems, and more particularly to a media stack height sensor for a finisher having a stapler.
2. Description of the Related Art
When stapling sheets of media that have been printed, the height of the media must not exceed a certain amount to avoid damaging or jamming the stapler head. In prior art staplers, height measurement was done by the use of a rotating link driven by a solenoid. When no media sheets were present, the end of the rotating link would be in its lowest position and a flag mounted thereon and moved by the link would interrupt an optical beam sensor. As media sheets to be stapled are fed into the staging area, the media sheets would raise the end of the link, and, when the number of media sheets exceeded a predetermined maximum height, the link rotates to a position where the flag no longer interrupts the optical beam sensor signaling that the maximum capacity for the stapler has been reached. This system had several limitations including a large stack up tolerance due to the sensor to link to solenoid connection, delays in operation of the solenoid and no capability to determine the actual number of media sheets to be stapled. Thus it would be advantageous to have a stack height sensor assembly that has minimal tolerance stack up, eliminates the uncertainty in the operation of the solenoid and enables measurement of the actual number of media sheets to be stapled.